Freddie Mac this week told Wall Street analysts its estimated net income for the first half of the year came to $2.7 billion, $1.5 billion in the first quarter and $1.2 billion in the second. About $500 million of the year-to-date net came from derivatives. While the results suggest the GSE’s 2006 profits will sharply exceed last year’s $2.75 billion, analysts note that Freddie officials don’t expect to sustain the $500 million in gains on its derivatives in the second half of the year...